Class: Removing Moss, Mildew, Fungus and Associated Stains on Roofs and Killing the Root Bed

For most homeowners the beginning of spring brings with it a sense of growth and rebirth as the air turns warmer and the first flowers of the season begin to bloom.

Outside – the world takes on a renewed freshness as the ground sheds its winter coat. This is why spring has been an ideal time for doing a deep cleaning and more often than not it is the exterior of the house that is at the top of the list of projects. In the warmer climates the roof seems to always be the first priority.

If you’ve had experience with mold and mildew inside the home, you know the best mildew remover is chlorine bleach.  But outdoor, this is not the case.  Heavy duty cleaning usually calls for more heavy-duty mixtures and Prevail or a mixture of Prevail and chlorine bleach is the product of choice for many contractors throughout the country’s heaviest mold/mildew zones.

Most homeowners will call a contractor to perform roof stain removal cleaning services. More often than not, when the contractor takes on the job – bleach is their cleaning product of choice. Unfortunately, bleach is nothing more than a quick, temporary fix to the problem and will only dissolve surface mildew which means that it will reappear in a few short months.

The Mixture:

Prevail: Depending on the accumulation mix 1 to 1.5 pounds of Prevail to water and stir until the product is dissolved thoroughly.

Prevail mixed with Chlorine Bleach: After you have thoroughly mixed the desired amount of Prevail in water you can slowly add while stirring – up to 1 gallon of chlorine bleach to the Prevail mix.

Application Instructions and Precautions:

  1. Mixtures containing chlorine bleach can injure sensitive plants. Because it is difficult to totally protect them from the mix we recommend that you water soak all areas surrounding the house for at least 30-minutes prior to starting the job.
  2. Using a plastic pump-type garden sprayer or ShurFlo Pump, thoroughly soak the affected area with Prevail or the Prevail/bleach mix. Allow it to sit for 5-10 minutes.
  3. So that you do not chance damaging asphalt roofs power wash off at low pressure in the range of 800-1200 psi with water volume in the range of 5.6 gpm.


Caution: When using the roof wash cleaner do not leave bleach or any mixture containing bleach on the roof longer than 20-30 minutes. Long term exposure to bleach can damage most any surface and your roof is no exception. Because of its high sodium content bleach can severely damage asphalt roofs. Sodium causes an electrochemical reaction that reduces the elasticity of the asphalt making it stiff, brittle and can cause curling of the shingles.

Packaging: 40 lbs. Powder

Buy 1 5-Gallon Power Pak
Makes 5-Gallons of Concentrate


Buy 1 55-Gallon Drum Pak
Makes 55-Gallons of Concentrate

SALE $197.00

Buy 3 55-Gallon Drum Paks and save 10%


Buy 6 55-Gallon Drum Paks and save 15%


pH:    11.9-12.3

Caustic:    No

Rinsing:    Excellent

Chelation:    Excellent

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